Supervisory signaling system.



No. 853,287. PATENTED MAY 14, 1907.

- H. G. WEBSTER.

SUPERVISORY SIGNALING SYSTEM.

APPLICATION FILED SEPT.19, 1903.

abs an V ID?- i A u r'mg.

rm: Nexus PETERS 0b,, WASHINGTON, n. c,

UNITED STATES.

PATENT EEICE.

HARRY G. WEBSTER, OF CHICAGO, ILLINOIS, ASSIGNOR TO STROMBERG- CARLSON TELEPHONE MANUFACTURING COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

SUPERVISOR! SIGNALING SiSTEM,

Specification of Letters Patent.

Patented May 14, 1907.

Application filed September 19, 1903. Serial No. 173,772.

(l/ZZ whom it may concern:

Be it known that I, HARRY G. W'EBs'rER, a citizen of the United. States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Supervisory Signaling Systems, of which the following is a lull, clear,

concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to telephone exchange systems, and its object is to provide such. a system which will be of great simplicity and reliability in operation.

:5 In the accompanying drawing I have illustrated. a preferred embodiment of my invention.

In this drawing I have illustrated at each of the substations A and B well known instrument sets, in each of which there is provided a switch hook 1, which when in its normal depressed condition, due to the weight of the receiver 2, serves to connect between the line limb 3 and the ground G a call-bell 4 and a serially connected condenser 5. In its upper position, due to the removal of the receiver 2, the switch. hook serves to connect between the line limb 3 and the line limb 6 a battery transmitter 7 and the primary 8 of an induction coil whose secondary 9 is included in circuit with the receiver 2. Any other suitable instrument circuit may, of course, be employed. The line limbs 3 and 6 lead to the central exchange C and to the positive and negative terminals of a common battery 10, the negative terminal being shown as grounded. Between the positive pole of the battery 10 and the line limb 3 there is serially included a winding 1 1 of a line relay 12, whose other accumulative winding 13 is serially included in the circuit between the line limb 6 and. the negative grounded pole of the common battery 10. It will be seen that the circuit between the common battery 10 and the line limbs 3 and 6 is at all times continuous and includes no relay or ack contacts.

As will hereinafter more fully appear, a talking current is supplied to the substation apparatus wholly through the line relay 12, the windings of which may be made of substantially the same resistance and impedance and inductively balance the telephone line circuit. The line relay 12 controls by means l of its armature 14 a local illuminating circuit through a line signal 15, which is shown as a small incandescent lamp. Multiple jacks 16 16 are provided, the tip spring 17 of these jacks being connected with the line limb 6, while the sleeve springs 18 are all permanently connected with the line limb 3. Each. jack is also provided with switching mechanism, whereby the insertion of a plug within a jack causes a break in the continuity of the local illuminating circuit through the associated. line signal. In this instance each jack is shown as provided with a pair of contacts 19, these contacts being serially con nected through all of the multiple jacks associated with one line and the last spring of the series is connected with the opposite pole of the common battery from that with which the lamp at 15 is connected, in this instance the last spring being shown as connected by means 01 a ground return with the negative pole of the common battery 10. Each of the acks is provided with a testing thimble 20, all of the test thimbles of the multiple jacks connected with any one line being connected together by means of a conductor 21.

The operators cord circuit comprises an answering plug 22 and a calling plug 23, the tip contacts 24 and 25 of these plugs being connected by means of a tip strand which comprises two conductively insulated portions 26 and 27. These conductively insulated portions of the cord strands, however, are inductively related for the transmission of telephonic voice currents either by means of a repeating coil or a condenser 28, as shown herewith. The sleeve contacts 29 and 30 of the cord connecting plugs are similarly connected by portions of a sleeve strand 31 and 32, those portions of the sleeve strand being connected through a condenser It will thus le seen that a portion of the cord circuit which is conductively connected with a calling line is never condtctiv'ely connected with the called line so that the two lines are conductively insulated for direct currents so far as the cord connecting apparatus is concerned.

Connected in bridge of the cord strands 26 and 31 is a supervisory relay 34, which is desirably of comparatively high resistance and of some impedance. The supervisory relay 35 is similarly connected in bridge of the cord strands leading to the calling plug. The supervisory relays each control by means of an armature 36 or 37 a supervisory signal lamp 38 or 39, as the case may be.

The usual operators listening key 40 is provided, the manipulation of which serves to connect the operators telephone 41 in bridge of the cord circuit. For testing purposes, which will more fully hereinafter appear, I have shown the operators telephone as provided with two coils, the common terminal of which is connected to the ground G. The induction coil is provided with a divided secondary comprising coils 42 and 43, and with a correspondingly divided pri- -mary having coils 14 and 45. The operators transmitter 46 may be connected with the primary winding through a local battery 47. The ringing key 18 is provided to connect the ringing generator 49 between the sleeve strand 32 and the ground G. The manipulation of this ringing key also connects the resistance 50 between the positive pole of the battery and the tip strand 27, whereby the coil 13 of the line relay of the called line is energized, and during the manipulation of the ringing key.

The operation of my improved system will now become apparent. The subscriber at substation A when desiring telephonic connection removes his receiver 2 from the switch hook 1 thereby closing a conductively continuous path between the line limbs 3 and 6. The circuit thus closed through the line relay 12 causes an attraction of the armature 14 to actuate the line signal, which in this instance is shown as the small incandescent lamp 15. The illumination of this lamp, due to current flowingthrough the local circuit including the armature 1 1 and the line signal controlling contacts of the jacks 16 notifies the operator of a call. She thereupon inserts her answering plug 22 within an answering jack associated with the line to substation A. The insertion of this plug in the first place causes a break in the connection between the local signal controlling springs 19, whereupon the circuit through the line signaling lamp 15 is broken to cause the extinguishment of this lamp. The insertion of the answering plug within the line jack 16 causes a connection of the supervisory relay 34 in bridge of the line limbs 3 and 6 to substation A. The circuit through the substation apparatus is of comparatively low resistance, while the resistance of the supervisory relay 341 is desirably quite high. At any rate, the adjustment of this supervisory relay is made such that when it is connected in shunt or multiple with a subscribers instrument set this relay is not sufliciently energized to cause the attraction of its armature 36. The supervisory signaling lamp 38 is, therefore, not caused to glow upon the insertion of the plug within a jack connected with a substation in which the telephone circuit is conductively closed for the passage of direct currents. The operator after thus inserting the answering plug manipulates her listening key to connect her telephone set in bridge of the cord circuit and by conversing with the calling subscriber she learns the number of the desired connection. Learning that substation B is desired, the operator then inserts her calling plug 23 within a line jack 16 associated with the line to substation B. The insertion oi? this plug at once causes a break in the local illuminating circuit having the line signal associated with the line to substation B, whereupon the subsequent energization of the relay 12 cannot cause the illumination of the associated lamp 1.5. The insertion of this plug also serves to at once connect the supervisory relay 35 with the poles of the common battery 10, this circuit being traced as follows: from the positive pole o'l. common battery 10 through winding 11 ol the line relay 12, line limb 3, to sleeve spring 18, sleeve contact of plug 23, sleeve strand 32, supervisory relay 35, tip strand 27, tip contact 25, tip spring 17 of the jack 16, line limb 6, winding 1.3 of the line relay and thence back to the grounded negative pole of the 9 common battery 10. There is as yet no path aflorded through the substation apparatus at B in shunt or multiple of the supervisory relay 35. Sullicient current is, therefore, caused to pass through the supervisory relay to energize the same to cause the attraction. of the armature 37, whereupon the supervisory signaling lamp 39 is caused to glow to indicate that the line circuit at substation B is not completed.

After inserting the calling plug, the operator manipulates her ringing key 48 to con.- nect the generator 4-9 between line limb 3 and ground G, whereupon the signal bell 4 at substation B is actuated to call the subscriber to his phone. At the same time the resistance is connected with. the tip strand 27, whereby a flow of current through the line relay 1.2 is maintained. It is o'l course apparent that the attraction of the armature 1 1 of the relay 12 will have no eil'ect upon. the line lamp 15, for the reason that its locz .l circuit has already been broken. between. the springs 19 upon the insertion ol the plug within one of the multiple jacks. The subscriber at substation B in answering the call removes his receiver from the switch hook thereby closing the conductively continuous path between the line limbs 3 and 6. This path is of comparatively low resistance and, being in shunt of the supervisory relay 35, this relay is deprived of the greater part of its current. The resulting partial deucrgization permits the retraction of the armature 37 to open the circuit through the associated supervisory lamp 39, thereby indicating to the central station operator that the call has been answered.

While it forms no essential part 01'' my present invention, I have shown means whereby the operator before attempting to call the subscriber at substation B may test the condition of his line. It will be seen that the insertion of a plug within a jack causes the connection of the testing thimble 20 with the sleeve spring 18, by means of the sleeve contact with the plug test. In this manner the test thnnble of a busy line is connected with the positive pole of the battery 10 and is thus charged to a potential only slightly less than that of the positive pole of this battery. Before inserting a calling plug within the jack of a called line, the operator manipulates her listening key 40 to connect her telephone set in bridge of the cord strands and then applies the tip contact 24 of the calling plug to the test thimble of the desired line. It this line is not in use no eiiect is produced for the reason that the test thiinbles are normally (:lisconnected both from current and from the battery 10. If, however, the test thimbles have been connected with the positive battery of the pole by the insertion 01 a plug at some other section of the multiple switchboard, the application of the testing tip contact 25 to a test thimble will cause the closure of the following circuit: from the positive pole of the battery 10 through the winding 11, line limb 3, sleeve spring 18, the sleeve contact of the already inserted plug at some other section of the switchboard, the test thiinhle 20, tip contact 25 of the calling plug, tip strand 27, thence through coil 42 of the induction coil, one winding of the operators telephone 41, and thence to ground G, which is connected with negative pole of the common battery 10. The click produced in the operators telephone by the closure of this circuit will indicate to her that the line is in use. The subscribers upon completing their conversation, either one or both replace their receivers upon the substation switch hooks. In placing his receiver upon the switch hook the subscriber breaks the conductively continuous path in shunt of the connected supervisory relay. The full current flowing through the line relay is thus caused to pass through the connected supervisory relay whereupon the same is energized to cause the attraction of its armature and the consequent illumination of the supervisory lamp, whereby the operator is notified of the desired disconnection. The pervisory arrangement herein shown is double whereby each subscriber controls his own supervisory signal.

I do not wish to be limited to the precise construction herein shown, as many changes may be made by those skilled in the art without departing from the spirit and scope of my invention, but

Having described myinvention I claim as new and desire to secure by LettersiPateli t 1. In a telephone exchange system, the combination with a telephone line extending by its limbs from a substation to an exchange, of a source of current at the exchange permanently connccted with both limbs of said line and adapted to supply talking and signaling currents to said line, a line relay included. in said line circuit, spring jacks connected with said. line, a line signal circuit controlled by said line relay, contacts in said spring jacks normally serially included in said line signal circuit, actuation of substation apparatus causing completion of the line signal circuit, a cord circuit at the central exchange for connecting lines together for conversation, a supervisory relay connected in bridge of the cord strands, and a supervisory signal circuit controlled by said supervisory relay, connection of the cord circuit plug with any spring jack causing connection of said supervisory relay with the source of current, connection of said cord circuit with a spring jack also mechanically causing interruption of said line signal circuit.

2. In a telephone exchange system, the combination of a telephone line extending from a central exchange to a substation, of a source of current at the central exchange connected with the line limbs of the telephone line, a line relay in said line circuit, spring jack having line contacts connected with the limbs of said line, normally closed auxiliary contacts for said spring jack, a line signal circuit controlled by said line relay and normally including said closed. auxiliary contacts, actuation of substation apparatus causing energization of said line relay to cause closure of the line signal circuit, a cord circuit at the central exchange, a supervisory relay connected in bridge of the cord strands, and a supervisory signal circuit controlled by said supervisory relay, connection of the cord circuit plug with any spring jack causing connection of said supervisory relay with the source of current, connection of the cord circuit plug with said spring jack also causing said auxiliary contacts to be opened whereby said line signal circuit is opened.

3. In a telephone exchange system, the combination with a telephone line exten ding from a substation to a central exchange, of a source of current at the exchange perinanently connected with both limbs of said line, a line relay included in said line circuit, a line signal circuit controlled by said line relay, spring jacks having line contacts connected with the line limbs, auxiliary normally closed contacts for said spring jacks normally serially included in said line signal circuits, a cord circuit at the central exchange, and a supervisory relay connected. in bridge of the cord strands, actuation of substation apparatus causing energization o't said line relay to close the line signal circuit, a connection ol the cord circuit plug with. any spring j act: causing said supervisor-y relay to be connected in bridge of the line limbs and said source of current, connection of said /lug with said spring iaclc also causing separation ot the corresponding auxiliary contacts whereby the line signal circuit is opened.

i. in a telephone exchange system, the combination with a telephone line extendin by its limbs from a substation to an exchange, of a source ol current at the exchange connected in bridge of the line limbs, a line relay included in said line limbs, a line signal local circuit partially controlled. by said line relay, spring jacks having line contacts permanently connected with said line limbs, auxiliary normally closed contacts for each spring jack, said contacts being normally serially included in the line signal circuit, a cord circuit at the central exchange, a supervisory relay connected in bridge of the cord strands and normally disconnected from any source of current, and a supervisory signal circuit controlled by said supervisory relay, connection of the cord circuit plug with any spring jack causin said. supervisory relay to be connected in bridge of the line limbs and ot the source of current, connection of said plug with said spring acl also causing separation of the associate l. auxiliary contacts whereby the line signal circuit is opened.

5. in a tel' one excanrge sysrem, the combination A h a telephone line extending from a suitstai ion to exchange, ot a source ol current at the exclr 'i'or supplying tall;- ing and signaling curre t; to the line, aline relay controlled by the line circuit. a local circuit at the central exchange controlled by line relay, a signal in saii local circuit, main spring jack con c s at tie central exchange connected w it leohone line, auxilii'iry spring jaclc contacts rely insulated 'l'rom main jack co is and from the telephone line and adapte: .ormally to comple"; the local circ it upon actuation ol' the line relay, a curl c it the cxchr a supervisin'y relay col ;rolling a supervison il circuit connected in iilre oi the cord strands, and m ans upon conieciion ol the cord apps s with the spring iaclzs ior causing said supervise relay to no cornice ed u i. the source of t and for causing actuation of the auxilia' y contacts to open the line signal circuit.

5. in a telephone exchai 1 com ration with a telephone line extend in from a substation to an exchange, et a sourc of current at too exchange for su 'iplying talliing and signaling currents to the line, a line relay controlled by the line circuit, a local circuit partly controlled by the line relay, a signal in said circuit, spring iacks having main i'zontacts connectml with the line, auxiliary contacts independent oi the line, said auxiliary contacts completing the control oil' the local circuit, a cord circuit at the central exchange, a supervisory relay coi'inected in irrir'ige oi" the cord strands, and means Wherel;y said eu'ipcrvisory relay may be energized and said auxiliary contacts may be actiutted to interrimt the line signal circuit upon the co'imcction of said cord. circuit with any spring jack. I

T. in telephone exchange system, the combination with a telephone line extending from a central cxchz'u'ige to a-si'ihstatiou, oil a source or current at the exchange for supplying talking and signaling currents to the line, line relay controlled by the line circuit, a line signal controlled by the line relay, spring jacks at the exchange, contacts 'tor said spring-jacks normally included serially in the line i nal circuit, actuation of substation appara tus causing actuation oi," the line relay to complete the local circuit to cause actuation of the line signal, a cord circuit. at the central exchange, a supervisory relay com'rectcd in liri d go of the cord strands, and means wheresaid supervisory relay may he energized and said auxiliary spring jack contacts may be actuated to open. the local circuit upon coi'ini tion oi said cord circuit with any spring acli.

8. in a telephone exchange system, the combination with a telephone line extending from a central exchange to a substation, ot a source of current at the exchange {or supplyin talking and signaling currents to the line, a. line relay controlled by the line circuit, a local sig a-l circuit i'i'icluding a signal controlled by said line relay, spring jacks at the exchange having main contacts connected with the telephone line, auxiliary contacts [or the spring jacks having only mechanical association with the main jack contacts and normally disposed to complete the local signal circuit when the line relay is actuated, a cord circuit at the central exchange, and. a supervisory relay controlling a supervisory signal circuit connected in lfiridge oil? the cord strands, connection ot a plug of the cord circuit with the spring jack mechanically causing actuation oi the auxiliary contacts to open the local signal circuit to destroy the signal COHDOCtlOll of said plug also causing the energimtion ol" said supervisory relay.

in witness whcreot, l. hereunto subscribe my name this 2nd; day o'l September A. 1)., l 903. 

